Aircraft, especially amphibian aircraft, including wings, outriggers, k-braces, v-struts, landing gear and tail members for same



' 1,906,823 OUTRIGGERS 14 Sheets-Sheet I ATTOREY I n. SIKORSKY AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS,

Filed June 17 1929 K-BRACES, V-STRUTS, LANDING GEAR, Am) TAIL MEMBERS FOR SAME May 2, 1933. s o s y 1,906,823 AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTBIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 1'7 1929 14 Sheets-Sheet 2 A ,F g.

I 1933. n. SIKORSKY 1,906,823

AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS,

STRUTS LANDING GEAR, AND TAIL MEMBERS FOR SAME K-BRACES, V-

Filed June 17, 1929 14 Sheets-Sheet 3 May 2, 1933. 4 s o s y 1,906,823

AIRCRAFT. ESPECIALLY AMPHIBI'AN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17, 1929 14 Sheets-Sheet 4 A TTORNE S.

ay 2, 1933.. a. SIKQRSKY 113%,823

AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June l7, 1929 14 Sheets-Sheet 5 May 2, 1933'.

1,906,823 OUTRIGGERS,

l. SIKORSKY AIRCRAFT, ESPECIALLY AMPHIBIA INCLUDING WINGS,

N AIRCRAFT, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17, 1929 14 Sheets-Sheet 6 i MINI} llllllll @or kSfiars ENTOR BY ATTORNEY May 2, 1933. s o g y LUGfiZg AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17, 1929 14 Sheets-Sheet 7 TOR / RNE;

1933. AIRCRAFT. ESPECI y 2, I. SIKORSKY ,8 3

ALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME 14 s eets-skeet 8 Filed June 17; 1929 INVENTOR.

l. SIKORSK-Y 7 1,906,823 AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS. OUTRIGGERS,

May 2, 1933.

K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17, 1929 INVENTOR ATTORNEY May 2, 1933. I s oRsKy 3,906,823 AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS K-BRACES, V-STRUTS, LANDING GEAR,- AND TAIL MEMBERS FOR SAME Filed June 17, 1929 14 Sheets-Sheet 10 INV NTOR "'1 I BY Z r ATTO EY May 2, 1933. 5 o 5 1,906,823

AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17 1929 14 Sheets-Sheet l 1 IN VEN TOR.

4 2 M TTO NEYS.

May 2, 1933. SIKQRSKY 1,906,823

AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 1'7. 1929 14 Sheets-Sheet l2 @or fil ofljig 1 NVENTOR BY M AT ORNEY may 2, 1933 SIKORSKY 1,906,823

AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed Uune 17, 1929 14 Sheets-Sheet l3 ATTORNEY May 2, 1933. g 5|KORSKY 1,906,823 AIRCRAFT. ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS,

K-BRACES, V-STRUTS, LANDING GEAR, AND TAIL MEMBERS FOR SAME Filed June 17, 1929 14 Sheets-Sheet 14 1 VENTOR Ill Patented ay 2, 1933 URI) STATES PATENT OFFIC IGOR SIKORSKY, OF COLLEGE POINT, NEW

YORK, ASSIGNOR TO SIKORSKY AVIATION AIRCRAFT, ESPECIALLY AMPHIBIAN AIRCRAFT, INCLUDING WINGS, OUTRIGGERS, K-IBRACES, V-STRUTS, LANDING GEAR AND TAIL MEMBERS FOR SAME Application filed June 17,

The present invention relates broadly to aerial vehicles and more particularly to the form, position arrangement and details of certain elements in the structure of aerial vehicles. It also deals with the various parts of said elements and the particular means and methods of joining these parts to secure a strong, rigid, light-weight and inexpensive structure.

The main object of the present invention is to increase the strength of aerial vehicles without materially increasing their weight, to make said vehicles safer during flight, landing and take-off. Another object resides in the development of a simple, inexpensive type of structure which can be put together rapidly by labor relatively unskilled in the art.

A still further object consists in materially increasing the natural aerodynamic stability of aerial vehicles by positioning certain of the elements of said vehicles in the particular relation to each other as described in this present application.

I propose further to so brace extension members as at all times to assure their rigidity even under the most severe stresses to which they may be subjected. Among other details, the present invention concerns an aerial vehicle body, its position with relation to other parts of the structure of said vehicle as well as the form, arrangement relative position, interrelation and details of fixed, movable and adjustable members attached to said body boat structure or forming a part of other aircraft structure attached to said body, and the relation of said members to each other as well as their relation to other structural elements of said aerial vehicle.

The invention further pertains especially to various combinations of any or all of said above improvements, their application to, their use on, in or in connection with individual hea-vier-than-aircraft units preferably of the multimotor land-water-air type, capable of navigating with equal facility on land, water or in the air.

I have found that in the construction of amphibian vehicles that it is sometimes pref- 1929. Serial No. 371,548.

(ijflble rather than attaching tail members directly to the body to position said tail members at a higher point preferably mounting them on outriggcrs attached to and extending rearwardly from a main wing surface connected to said boat structure.

I have found further that when the outriggors are given substantial width and are presented in vertical planes to the air when the aircraft is on even keel that these covered outxiggers have a marked stabilizing effect in the navigation of my aircraft.

In accordance with my preferred embodiment, my main wing surface is well above the water and my tail surfaces and Outriggers extending between and connected to said wing and said tail surfaces are substantially in line with said wing and also well above the water line on said body boat structure.

In a land machine which is also capable of navigating on the water as well as in the air, there is considerable merit in my opinion in shortening the vehicle bodyand in permitting the tail members to be indirectly attached to said body through outrigger members and struts connecting said Outriggers to said body in that when the machine is taking off from the ground, there is less danger of structurally injuring the body by dragging it on the ground too long or damaging the tail surfaces because of their short distance above the ground level.

In my design of amphibian, the tail surfaces are employed to carry a substantial portion of the weight of the vehicle when it is in flight. For this reason, I have employed a form of tail surface structure Well adapted to carry the loads imposed on it. I have further introduced a mechanism and method of altering the tail surface angle of incidence, and is thus made possible a very much lower landing speed which is a particular asset when the operator of the aircraft may find himself compelled to land either on a small patch of ground or a small area of water.

In designing the tail members, I have adopted a form of construction preferably wrought in metal and susceptible of cheap and rapid production by relatively unskilled and inexpensive labor.

In bracing the wings, outrigger members and tail in relation to the body of my aerial vehicle, I have found that struts placed in pairs on each side of the body can, in some instances, produce great rigidity in the structure and impart a large factor of safety to it when it is operating under difficult or unusual conditions.

By my present construction, I so mount the tail members as to direct landing stresses largely on the tail skid structure and cause the retractable landing gear to receive the stresses imposed by a-large portion of the weight occasioned by the engines, which are connected to the main wing. Furthermore, my control apparatus for altering the position of the wing surfaces hingedly mounted on the Outriggers is simple and effective, keeping the tail at all times in the desired relation to the outrigger members even though the control cables leading to this mechanism might be out of working order.

Where the term aircraft is used in the present application, it includes broadly any form of aerial vehicle capable of navigating through the air.

The term heavier-than-air aircraft unit of the land-water type designated a form of aircraft sometimes known as an amphibian. Other purposes and objects of my invention will become more clearly evident as the following description progresses and from the accompanying drawings forming a part of my disclosure. However, by no means is it intended to limit me to the structures shown beyond the broad sense of the invention as laid down and covered by the appended claims.

In the accompanying drawings:

Fig. 1 is a plan view of an amphibian embodying the improvements which are comprised in the present invention.

Fig. 2 is a front elevation of the amphibian.

Fig. 3 is a side elevation of the same.

Fig. 4 is a front elevation of the center portion of the amphibian.

Fig. 5 is a section on line 5-5 of Fig. 4.

Fig. 6 is a perspective of the amphibian showing the rudder controlmechanism.

Fig. 7 is a perspective of the amphibian showing the elevator control mechanism.

Fig. 8 is a similar perspective showing mechanism for adjusting the angle of the stabilizer.

Fig. 9 is a perspective of certain upper structural elements of the amphibian as seen from the rear.

Fig. 10 is a perspective of the empennage ilnfd supporting members as seen from the Fig. 11 is a plan view of a portion of the gmpennage and the supporting means there- Fig. 12 is a skeleton view in side elevation of the empennage and the supporting member therefor.

Fig. 13 is a side elevation of a portion of the empennage supporting means.

Fig. 14 is a section on line 14-14 of Fig. 13.

Fig. 15 is a section on line 1515 of Fig. 13.

Fig. 16 is a plan view of certain elements included in the stabilizer adjusting mechanlsm.

Fig. 17 is a section on line 17-17 of Fig. 16.

Fig. 18 is a section on line 1818 of Fig. 16.

Fig. 19 is a plan view of certain elements included in the stabilizer adjusting connections.

Fig. 20 is an elevation of an outrigger which forms an empennage supporting member.

Fig. 21 is an enlarged view of the left hand end of the outrigger as shown in Fig. 20.

Fig. 22 is a section on line 2222 of Fig. 21.

Fig. 23 is a section on line 23-23 of Fig. 21.

Fig. 24 is an enlarged elevation of a portion of the outrigger.

Fig. 25 is a section on line 25-25 of Fig. 24.

Fig. 26 is a section on line 2626 of Fig. 24.

Fig. 27 is an enlarged side elevation of a further portion of the outrigger.

Fig. 28 is a section on line 28 28 of Fig. 27.

Fig. 29 is a perspective showing the pivotal connecting means between an outrigger and a structural member of the stabilizer.

Fig.30 is a perspective. showing the manner of attaching the forward end of the outrigger to a structural member of the main plane of the amphibian.

Fig. 31 is a partial plan view showing the stabilizer adjusting mechanism.

Fig. 32 shows the stabilizer adjusting mechanism in side elevation.

Fig. 33 is an enlarged view partly in section of portions of the stabilizer adjusting mechanism.

Figs. 34 to 37 are perspective views of details involved in the stabilizer adjusting mechanism.

Fig. 38 is a skeleton view in side elevation of a vertical fin and a cross-section of the stabilizer.

Fig. 39 is a rear view of the vertical fin shown in Fig. 38.

Fig. 40 is a. section on line 4040 of Fig. 38.

Fig. 41 is a reverse view of a nose plate shown in Fig. 40.

Fig. 42 is an enlarged view partly in section of a portion of the structure shown in Fig. 40.

Fig. 43 is a section on line 43-43 of Fig. 38.

Fig. 44 is a rear elevation of the upper end of the fin shown in Fig. 38.

Fig. 45 is a section on line 45-45 of Fig. 38.

Fig. 46 is a side elevation of the lower corner of the fin shown in Fig. 38.

Fig. 47 is a rear elevation of the lower portion of the fin.

Fig. 48 is a perspective of a detail.

Fig. 49 is a section on line 49-49 of Fig. 46.

Fig. 50 is a section on line 50-50 of Fig. 46.

Fig. 51 is a plan view of a rudder frame.

Fig. 52 is an elevation of a rib or contour member involved in the rudder frame.

Fig. 53 is an enlarged view of the right hand end portion of the member shown in Fig. 52.

Fig. 54 is an enlarged elevation of a portion of the member shown in Fig. 52.

Fig. 55 is a section on line 5555 of Fig. 54.

Fig. 56 is an elevation of a further rib or contour member involved in the rudder frame.

Fig. 57 is an end view of the member shown in Fig. 56 as seen from the right of the latter figure.

Fig. 58 is a section on line 58-58 of Fig. 56.

Fig. 59 is a perspective of the right hand end portion of the member shown in Fig. 56.

Fig. 60 is a section on line 6060 of Fig. 51.

Fig. 61 is a section on line 61-61 of Fig. 51.

Fig. 62 is a section on line 62-62 of Fig. 51.

Fig. 63 is a section on line 6363 of Fig. 62.

Fig. 64 is an elevation of the upper end of a longitudinal rudder frame member.

Fig. 65 is a section on line 6565 of Fig. 64.

Fig. 66 is a. section on line 6666 of Fig. 64.

Fig. 67 is an enlarged elevation of the lower left hand portion of the rudder frame as seen in Fig. 51.

Fig. 68 is a section on line 68-68 of Fig. 67.

Fig. 69 is a bottom plan view of a portion of the rudder frame.

Figs. 70, 71 and 72 are perspectives of constructional details involved in the rudder frame. 7

Referring to the drawings, the numeral 80 denotes the body boat of the amphibian, an upper plane being positioned thereabove and consisting of wings 81 and 82, and a center section 83. Lower wings 84 and 85 project laterally of the body boat and are suitably connected with the upper plane by means of interplane struts suitably arranged. Pontoons 86 and 87 are supported beneath the outer ends of wings 84 and 85.

Motors or power plants 88 and 89 are sus pended beneath center section 83 somewhat in advance thereof and at each side of the body boat.

Outriggers 90 and 91 project rearwardly of center section 83 in symmetrical relation to the longitudinal axis of the body boat. At their rear ends, the outriggers support an empennage comprising a stabilizer 92, an elevator 93, a pair of rudders 94 and 95, and a pair of vertical fins 96 and 97, both of which may be seen in Fig. 6. The rear ends of outriggers 90 and 91 are interconnected by means of braces 98, 99 and 100, which are in substantially K-formation, the divergent members extending rearwardly and joining the outriggers substantially at their points of junction with stabilizer 92. In the plane of cross-member 98, the outriggers are connected by means of struts 101 and 102 with the stern of the body boat immediately above a tail skid 103, a substantially vertical compressible member 104 being interposed between the tail skid and the lower ends of the struts.

In order that the machine may be brought to rest with equal ease on land and water, in addition to the body boat, it is provided with landing wheels 105 mounted on axles 107 pivoted to the body boat for oscillation in vertical planes and braced against fore and aft distorted movements by members 106. Pivoted to the outer end of axles 107 are rods 108, having at their upper ends piston heads Working in tubular members or cylinders 109, the latter being pivoted at their upper ends to rigid strut members 110. Rods 108 are adapted to be projected or retracted relative to cylinders 109 by means of fluid under pressure admitted to the latter at one side or the other of the piston heads associated with the rods. In Fig. 4, a tank for the reception of the hydraulic medium is indicated at 120, this tank being connected by means of a conduit 121 with a pump or pressure generator 122 actuated by means of a lever 123 disposed within convenient reach of the pilots seats 138 which, as shown in Fig. 5, are disposed side by side in a pilots compartment 130. Outlet and return pipes 125 and 125 lead to a distributor 124 which may be controlled to send fluid under pressure either thr ugh tubes 109 to the upper ends of cylinders 109 or through tubes 109 to the lower ends of the cylinders, thus causing the projection or reiiba5ction of rods 108 and therewith wheels It will be noted that tubes 109 and 109 pass upwardly through a stream line housing 126 and laterally through branch housings 127 and 128. A further vertical housing 126' forms a continuation of housing 126,

these two housings serving a purpose which I will presently appear.

The two seats 138 are arranged for vertical adjustment on upwardly extending guide members 129, the vertical adjustment being effected through levers 133 cooperating with locking segments 135. Disposed between the seats are engine control levers 130 and hand wheels 131, by means of which the angular position of the stabilizer is controlled. Forward and centrally of the seats is a post 139 to the upper end of which is pivoted an arm 140 supporting a wheel 141, the arm being swingable relative to the post to bring the wheel in front of either seat. Fore and aft oscillation of post 139 causes appropriate movement of the elevator 93, while rotation of wheel 141 controls ailerons 142 and 143.

The control system for the movable ele ments of the empennage is indicated in Figs.

6 to 8. In Fig. 6, right and left hand pedals segments 146 and 147. Cables 148 and 149 are secured to segments 146 and 147, and by means of suitable sheaves are trained upwardly from the pilots compartment to the main plane center section through conduits 126 and 126'. mentioned abovef From the main plane, the cables are trained rearwardly between outriggers 90 and 91, and their ends secured to the ends of a two-armed lever 150 which is mounted on a vertical rock shaft 151 disposed in stabilizer 92. Rock shaft 151 has fixed thereto a lever 152 which, through links 153 and 154, is secured to levers 155 and 156 rigid on vertical rock shafts 157 and 158 likewise mounted within the outlines of stabilizer 92.

The ends of rock shafts 157 and 158 pro ject above and below the surfaces of the stabilizer and have secured thereto arms 159, 160, 161 and 162 which through suitable links are connected to brackets projecting from the upper and lower sections of the two rud ders so that all of the sections are controlled in dependence upon movements of rock shaft 151. Post 139 is pivotal about a horizontal shaft 163 and has rigid therewith, plates 164 and 165 extending above and below-the axis. To the upper and lower ends of these plates are respectively secured cables 166, 167, 168 and 169, these by means of suitably arranged sheaves being trained upwardly through conduits 126 and 126, and rearwardly to the upper and lower ends of two-armed levers 170 and 171 rigidly mounted on a frame memher 172 of elevator 93.

Hand wheels 131 of which one is shown in Fig. 8, are connected to a drum 173 which engages cables 174 and 175 so that upon rotation of the hand wheels, the cables are alternately paid out and drawn in. Cables 174 and 175 by means of suitable guide sheaves are trained upwardly through conduits 126 and 126', and rearwardly between outriggers 90 and 91. The rear ends of the cables are connected to a length of chain engaging a sprocket wheel 176, through rotation of which rods 263 and 264 may be simultaneously moved outwardly or inwardly relative to the sprocket, this movement being transmitted through bell crank levers 267 and 268 to links 181 and 182 connected to vertical fins 96 and 97. Fins 96 and 97 are in rigid connection with stabilizer 92 which is pivoted to the rear ends of the outriggers. Reciprocation of links 181 and 182 in the manner described, consequently causes angular adjustment of the stabilizer.

The above description will make clear the general mechanical construction of the aircraft and the control means for the movable members of the empennage. I shall now proceed to describe some of the specific constructional features involved in my invention.

Each of the outriggers 90 and 91 is of identical construction and only one may be described. Referring to Figs. 20 to 30 in particular, the outrigger 90 is shown as comprising upper and lower bulb flanged T-memhers 183 and 184 in spaced relation with their ends somewhat converging. The T-members are connected by truss units 185, each unit consisting of a pair of U-members 186 and 187 in back to back relation with their ends riveted to the T-member flanges. To enhance the rigidity, the truss units may be secured to the T-member webs through plates 188 and 189 as shown at the right of Fig. 20 and also in Figs. 27 and 28, the truss members being riveted at a plurality of points through these plates and through the T-member flanges, and through the projecting margins of the plates and spacers 190. At their forward ends, the T-melnbers are joined by plates 190 and 191, these and the T-member flanges being perforated to receive bolts 192 and 193 which secure the outrigger to connector brackets 194 and 195 fixed to the rear spar 196 of the main plan center section in alignment with a main plane compression member 197.

The lower T-member 184 has secured to its lower face at the rearward extremity of its horizontal portion, an anchor member 198 for the upper end of strut 101. The rear ends of the T-members have secured thereto plates 199 and 200, whose projecting noses are provided with aligned apertures adapted to receive a bolt 201 passing likewise through aligned apertures in angle brackets 202 and 203 secured to the forward face of the forward spar 204 of the stabilizer. Through this connection, the stabilizer is permitted to be angularly adjusted relative to the outriggers about bolts 201, Preferably, plates 199 and 200 are secured to the flanges of members 183 and 184 through spacer blocks as at 205 and 206.

As will be clear from the above description, the outriggers are of considerable vertical extent as compared to their transverse horizontal dimensions. The relatively large vertical area of the outriggers adds a considerable measure of stability to the machine, the outriggers as is particularly clear from Figs. 9 and 10 being provided with covers of suitable material.

As is particularly shown in Figs. 12 and 38,- the stabilizer 92 includes front and rear spars 204 and 207, a compression memher 208 being interposed between spar members in alignment with each of the outriggers. A hanger bracket 209 for the elevator is secured to the rear face of rear spar member 207 in alignment with each of the compression members just mentioned.

secured thereto.

Each of the vertical fins 96 and 97 comprise upper and lower sections in the vertical plane of a compression member 208. As shown in Figs. 38 to 47 in particular, the upper section of fin 96 comprises a front spar member 210 and a rear spar member 211, these members being composed of U-channels in spaced relation, member 211 being substantially vertical and member 210 upwardly and rearwar-dly inclined. The lower ends of members 210 and 211 are joined by means of a channel member 212 and their upper ends by flanged plates 213 and 214. Intermediate their tops and bottoms, members 210 and 211 are connected by means of U-section truss members 215, 216 and 217. The adjacent converging ends of members 215 and 216 are connected to member 210 through the intermediary of plates 220 and 221, and the legs of a bifurcated member 222 are secured to member 210 through the intermediary of these plates. At its forward extremity member 222 is provided with an eyelet 223, this eyelet projecting beyond the leading edge of the fin as defined by nose plates 224 which are secured at suitable intervals to the forward face of member 211. Suitable contour members 225 and 226 (see particularly Figs. 40 and 43) have their forward extremities secured to the rear portions of the nose plates and their rear portions to member 211. The fin section is secured to spar members 204 and 207 of the stabilizer by means of angle brackets 227 secured to the forward portions of members 210 and 211. Secured to the rear face of member 211 at its upper and lower extremities are knuckles 28 and 229 adapted to receive between them the noses of cooperating hinge elements 230 and 231 secured to the front face of a channel member 232 which constitutes the main frame member of rudder 94, Fig. 51.

Referring to Figs. 51 to 72, reference numeral 233 denotes a number of nose members projecting forwardly of member 232, the lowest of these nose members lying immediately above the topmost contour element of fin 96. The forward ends of these nose members are apertured to receive a contour member 234 which passes through a recess in the upper reduced end of member 232, and is secured at its rear extremity to a V-section strip 235 defining the trailing edge of the rudder. The upper end of strip 235 is connected to member 232 through tail defining contour elements 236 which are in alignment with the upper nose members 233.

Each of nose members 233 is in the form of a dished-plate having rear extensions 233' adapted to overlie the somewhat rearwardly convergent side flanges of member 232 to be The nose member is additionally secured to member 232 through an integral flange 233" which is riveted to the front face of member 232. Each contour element 236 comprises trussed contour strips 236 and 236", whose inwardly offset divergent extremities are adapted to be secured to the inner faces of the side flanges of memher 232 in alignment with a nose member 233 and by means of the same rivets which secure the latter. The lower rear portion of the rudder has surfaces defined by contour elements 237 which are arranged in truss formation. The lowermost member 237 is upwardly and rearwardly inclined so as to avoid interference with movements of the elevator, and is connected to the lower extremity of member 232 by means of an angle bracket 238 shown as a whole in Fig. 70. The substantially horizontal upper face of bracket 238 has secured thereto a plate 239 having an integral arm 240 provided at its extremity with an eyelet 241 through the intermediary of which the actuating link for the rudder is secured to the arm.

To the forward face of member 232 intermediate members 230 and 231 is secured a fairing member 242. Spring clips 243 and 244 extend above members 230 and 231 in position to prevent accidental upward dis placement of the bolts through which these latter members are secured to knuckles 228 and 229.

Each of the rudders 94 and 95 is composed of balanced upper and lower sections, some what outwardly flared as shown in Fig. 11, and each provided with an arm 240. Each of these arms is in connection, by means of a link, with a lever arm 159 to 162, Fig. 6, only the upper links 245 and 246 being clearly visible in this last named figure and in Fig. 11. The operation will be clear if reference is had to the description in connection wit Fig. 6.

The elevator 93, Fig. 11, has a main spar 247 which,through suitable forward extensions as at 248, supports a pivot rod 172 engaged in the apertures 209 of hanger brackets 209, Fig. 38. As has been described in connection with Fig. 7, levers 170 and 171 are fixed to member 172.

The adjusting mechanism for the stabilizer has been generally described with reference to Fig. 8, the details of construction being particularly shown, however, in Figs. 9 to 19 and 31 to 37.

Referring to Figs. 9 and 10, it will be seen that the K-brace described in connection with Fig. 1 and comprising members 98, 99 and 100 also includes lower members 98, 99 and i 100, these being connected together by means of an upright 249 upon which are arranged guides 250 for the cables leading to the upper arms of levers 170 and 171. The cables to the lower arms of these levers, as well as the cables leading to the rudder lever 150, are guided by a cleat 251 secured to the intermediate portion of brace 98. Brace 98 is constituted essentially by a tubular memher 252 of square section, in the ends of which are secured shanks 253 formed on blocks 254 and 255 secured to the upper T-members of the Outriggers, see Figs. 31 and 36 in particular. At the intermediate portion of member 252 are secured hanger brackets 256 and 257, which support bushings as at 258, Fig. 37, in which is rotatable a sleeve 259 provided with opposite internal threads at its ends. A sprocket wheel 176 has a hub 261 provided with diametrically opposite grooves 261 and 261" in which engage the ends of a locking plate 262, which likewise project through diametrically opposite slots in sleeve 259, to retain the sprocket wheel on sleeve 259 and against rotation thereto. The sprocket wheel is arranged between members 256 and 257, and the ends of plate 262 engage the latter members to prevent longitudinal displacement of the sleeve.

The oppositely threaded ends of bars 263 and 264 engage in the threaded ends of sleeve 259, the outer ends of these rods being supported for reciprocation in brackets 265 and 266, the extremities of the arms being provided with knuckle members 263 and 264 in connection with plates 267 and 268 pivotally mounted in horizontal kerfs formed in blocks 254 and 255 which esentially are bell crank levers. The connections are established by means of pins as at 269, Fig. 16, fixed to the plates and engaging slots in the knuckle members so that pivotal movements of the plates will not be interfered with. At other points, plates 267 and 268 are connected with links 181 and 182 which, at their rear ends, are in connection with connector members 222 fixed to the vertical fins.

It will be evident from the above that rotation of sprocket 176 in one direction will project rods 263 and 264 outwardly of sleeve 259, while rotation of the sleeve in the other direction will draw the rods inwardly of the sleeve. Thus plates 267 and 268 may be simultaneously rocked about their axes to move links 181 and 182 in either direction to rock the stabilizer about its pivotal axis. Since all of the empennage members are mounted in connection with the stabilizer, all of them will partake in the movement of the latter.

As has been mentioned in connection with Fig. 8, cables 174 and 175 have interposed between their ends a short'length of sprocket chain which is in engagement with sprocket 176. This length of chain is indicated at 270, Fig. 10.

It will be understood that the described embodiment of my invention is merely illustrative of myinvention, and I do not limit myself except as determined in the following claims.

I claim:

1. In an aircraft, a plane, a pair of outriggers projecting rearwardly therefrom, all

empennage pivoted to the rear end of the outriggers on a horizontal axis, a cross member attached to said Outriggers and means for adjusting the empennage about said axis, said means including actuatin mechanism mounted on said cross member tween said Outriggers.

2. In an aircraft, a plane, a pair of outriggers projecting rearwardly therefrom, an empennage pivoted to the rear end of the outriggers on a horizontal axis, a cross member attached to said Outriggers and means for adjusting the empennage about said axis, said means including a screw projected and retracted element mounted on the outrigger.

3. In an aircraft, a plurality of empennage supporting means, cross members attached to said empennage supporting means including a K brace an empennage supported thereby for pivotal movement on a horizontal axis,

and means for adjusting the empennage about said axis, said means including a screw projected and retracted element mounted on said cross members transversely of the longitudinal axis of the aircraft, means oscillable by said element, and a link connecting said oscillable means and the empennage.

4. In an aircraft, a plane, a plurality of Outriggers projecting rearwardly therefrom, an empennage pivoted to the rear ends of said Outriggers on a horizontal axis, a brace interposed between the Outriggers forward of the empennage in a plane perpendicular to the longitudinal axis of the aircraft, a rotatable sleeve suported on said brace in parallel relation thereto, said sleeve being oppositely screw-threaded at its ends, a threaded rod engaged in each end of the sleeve, a bell crank lever in connection with each of said rods, links connecting said levers and the empennage at points vertically removed from the axis of the latter, and means to rotate said sleeve.

5. In an empennage including a stabilizer and a pair of pivoted vertical rudders, a T-shaped lever mounted in the stabilizer, a pair of links connected with one of the lever arms, a bell crank lever in connection with each link, and a second link in connection with each bell crank lever and an arm fixed to each rudder.

6. In an aircraft, a body, a plane above the body, an outrigger extending rearwardly from the plane, an empennage hingedly supported at the rear end of the outrigger, a strut between the rear end of the outrigger and the body, and a fluid and spring cushioned tail skid attached to the body immediately below the lower end of said strut.

7. In an aircraft, a body, a plane above the body, a pair of power plants connected to said plane a pair of Outriggers extending rearwardly from the plane in alignment with said motors and in symmetrical relation to the longitudinal axis of the body, struts in- 

